1. Field of the Invention
The present invention relates to an apparatus for monitoring a lamp, system having the apparatus for monitoring a lamp, a backlight assembly having the apparatus and a liquid crystal display apparatus having the apparatus for monitoring the lamp. More particularly, the present invention relates to an apparatus for monitoring the lamp that senses a working status of the lamp and prevents the apparatus from malfunctioning due to a signal interference, a system for monitoring the lamp having the above-mentioned apparatus for monitoring the lamp, a backlight assembly having the above-mentioned apparatus for monitoring the lamp and a liquid crystal display apparatus having the above-mentioned apparatus for monitoring the lamp.
2. Description of the Related Art
Generally, when an electric field is applied to liquid crystal, an arrangement of liquid crystal is adjusted, so that optical transmittance of the liquid crystal is changed.
A liquid crystal display (LCD) apparatus uses the liquid crystal to convert an electrical signal into a visible image.
The LCD apparatus has merits such as lightweight and small size compared to a cathode ray tube typed (CRT) display apparatus. However, the LCD apparatus has a problem that the LCD apparatus may not operate in a dark place since the liquid crystal cannot generate a light spontaneously.
Recently, LCD apparatuses capable of displaying an image in a dark place have been developed. Most of the LCD apparatuses that are recently developed have a lamp. The LCD apparatus having a small or medium display size may display an image of high display quality only by using one lamp or two lamps.
Number of the lamps is increased when display size of the LCD apparatus is increased. Generally, about ten to twenty lamps are required for large size LCD apparatus. The large size LCD apparatus having ten to twenty lamps may be improved in brightness, however, the large size LCD apparatus has various problems due to using a plurality of lamps. High manufacturing cost, large size and heavy weight of the LCD apparatus are resulted from an increase of the number of driving apparatus supplying a driving power to the lamp corresponding to the number of the lamps.
Recently, an LCD apparatus having a plurality of lamps that are connected to each other and disposed in parallel to each other has been developed. The lamps are turned-on simultaneously by using one or two driving apparatuses.
Accordingly, the LCD apparatus may advantageously decrease the number of required lamp driving apparatuses. However, when one of the lamps is turned off, other lamps are overloaded, so that a lifetime of properly working lamps is decreased and damage or fire of the properly working lamps may occur.